import sys 
# sys.stdin = open('input.txt', 'r')  
# sys.stdout = open('output.txt', 'w') 
t = int(input())
if t >= 30:
	print("Yes")
else:
	print("No") import sys sys t = int(input()) t int(input()) int input() input if t >= 30:
	print("Yes")
else:
	print("No") t >= 30 t 30 print("Yes") print "Yes" print("No") print "No" t = int(input()) int(input()) t
import sys 
# sys.stdin = open('input.txt', 'r')  
# sys.stdout = open('output.txt', 'w') 
t = int(input())
if t >= 30:
	print("Yes")
else:
	print("No")